Allow me to introduce you to Nix - The Purely Functional Package Manager.
Nix is a powerful package manager for Linux and other Unix systems that makes package management reliable and reproducible. It provides atomic upgrades and rollbacks, side-by-side installation of multiple versions of a package, multi-user package management and easy setup of build environments.
We will also look into NixOS - The Purely Functional Linux Distribution.
NixOS is a Linux distribution with a unique approach to package and configuration management. Built on top of the Nix package manager, it is completely declarative, makes upgrading systems reliable.
Rok Garbas is a web programmer, when not writing Javascript, he usually scripts in Python. He started using Nix and later NixOS (linux distribution built around Nix) 3 years ago. Currently he is working at RhodeCode, where he solves packaging problems for large enterprises.